How to validate JSON against a schema
Paste a JSON document into JSON Document and its rules into JSON Schema. Choose a value in Schema draft. JSON Schema Validator reports each schema violation with a JSON Pointer, a dot-path, and the document's line and column. Syntax errors appear separately, and the editor text remains unchanged.
- Paste the JSON you want to check into JSON Document.
- Paste the rules into JSON Schema.
- Choose the matching draft in Schema draft.
- Click Load sample to fill both editors with the built-in document and schema.
What validation results show
The page waits until both inputs parse as JSON. A conforming document produces No violations found. Errors appear in a table with Path, Location, Violation, and Schema rule. Path shows a JSON Pointer and a dot-path; Location shows the document line and column.
{"email":"not-an-email"}
Schema: {"properties":{"email":{"type":"string","format":"email"}}}
Path: /email
Location: Line 1, col 10
Violation: must match format "email"
Schema rule: #/properties/email/formatA missing required property or a root-level rule can point to the containing object. Copy errors (TSV) copies the error rows as tab-separated text when errors are available and clipboard access works.
Which JSON Schema drafts can you choose?
Schema draft lists Draft 4, Draft 6, Draft 7, 2019-09, and 2020-12. Pick the draft used by the schema. Draft 4 reads exclusiveMinimum and exclusiveMaximum as booleans, while later drafts read them as numbers. Older drafts use tuple-style items; 2020-12 uses prefixItems.
What this JSON Schema Validator checks
The validator checks types, required properties, enums, constants, number and string limits, patterns, selected formats, arrays, object properties, dependencies, conditional rules, and combinations such as allOf, anyOf, oneOf, and not. Local $ref pointers inside the pasted schema work; remote references are not fetched.
Recognized format checks include email, date, date-time, uri, uuid, and IP addresses. These checks are best-effort rather than full RFC validation. Unknown schema keywords have no effect in this implementation. Both inputs must be valid JSON, and the document is read for checking without reformatting or mutation.
Checking API responses and configuration objects
Paste an API response with its schema to check required fields, types, and an email format. The returned path identifies the value that needs attention. For a configuration object, set additionalProperties to false and the table reports each unexpected key.
If a project changes schema drafts, check the same document again after changing Schema draft. A schema with local definitions reports the nested path and the schema rule for the failing $ref branch.
When to use this validator or another JSON tool
JSON Validate Tools groups browser-based checks for JSON data. Choose JSON Validator & Formatter when you need syntax validation, formatted output, a tree view, or copy and download actions. Choose JSONL Validator & Formatter when the input is JSON Lines or NDJSON and each nonblank line needs separate parsing.
Frequently asked questions
How do I validate JSON against a JSON Schema?
Paste the document into JSON Document, paste the rules into JSON Schema, and choose the matching Schema draft. Results update as either input changes.
Which Schema draft should I choose?
Choose Draft 4, Draft 6, Draft 7, 2019-09, or 2020-12 to match the schema you pasted. The selection changes draft-specific keywords and array rules.
What happens when my JSON has a syntax error?
Invalid JSON syntax appears separately from schema violations, with a line and column for the parsing problem. Schema checks wait until both JSON inputs parse successfully.
Does JSON Schema Validator change or format my document?
JSON Schema Validator leaves the source document unchanged. It parses the text to validate values and locate errors, then keeps the original editor content.
Are JSON Document and JSON Schema sent to a server?
The validator processes both inputs in your browser and does not send them to a validation server. The page can load analytics scripts separately from validation.